Posted by Alex (87.119.159.220) on September 03, 2007 at 15:39:17:
We are using anodised aluminium extrusion parts as decorative elements on appliances. Parts are brushed and then anodized to get "stainless steel" like color (size is app. 30 x 90 cm). We noticed that after a few weeks of keeping products packaged in warehouse, we get "white" irregular areas on about 30% of the products. Microscope pictures show small bubbles just below the surface in anodised level (not in aluminium). We can not observe this marks - areas on fresh from production pieces. Any idea what might cause this problem?